Date issued

Journal

Biodiversity and Conservation

Type

Article

Language

en

Publisher

Springer Verlag (Germany)

Embargo

2018-05-26

Reason for embargo

Under embargo until 26th May 2018 in compliance with publisher policy

Abstract

Gabon hosts nesting grounds for several sea turtle species, including the world’s largest rookery for the leatherback turtle (Dermochelys coriacea), Africa’s largest rookery for the olive ridley turtle (Lepidochelys olivacea) and smaller aggregations of the hawksbill turtle (Eretmochelys imbricata) and green turtle (Chelonia mydas). To assess the level of incidental captures of turtles by the Gabonese trawl fishery, an onboard observer program was conducted in the period 2012–2013. A total of 143 turtles were captured by 15 trawlers during 271 fishing days. The olive ridley turtle was the main species captured (80% of bycaught turtles), with mostly adult-sized individuals. The remaining 20% included green turtles, hawksbill turtles, leatherback turtles and undetermined species. Bycatch per unit of effort (BPUE) of olive ridley turtles varied greatly depending on the period of the year (range of means: 0.261–2.270). Dead and comatose turtles were 6.2 and 24.6% respectively (n = 65). By applying the available fishing effort to two BPUE scenarios (excluding or considering a seasonal peak), the total annual number of captures was estimated as ranging between 1026 (CI 95% 746–1343) and 2581 (CI 95% 1641–3788) olive ridley turtles, with a mortality ranging from 63 (CI 95% 13–135) to 794 (CI 95% 415–1282) turtles per year depending on the scenario and on the fate of comatose turtles. Such a potential mortality may be reason for concern for the local breeding population of olive ridley turtles and recommendations in terms of possible conservation measures and further research are given.

Funders/Sponsor

Funding for the observer program and training was
provided by the Government of Gabon, the Marine Turtle Conservation Fund (Fish and Wildlife Service, US
Department of the Interior), NOAA (US Department of Commerce, Division of International Affairs), UK
Darwin Initiative (Department for Environment Food and Rural Affairs), and the World Wide Fund for
Nature.

Description

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.